Propane Tank

ScottG wrote:
The techs probably couldn't find it because it's so unusual for a tank itself to leak.
Frankly, I wouldn't think to look there either.

I recently inherited a tank that expired in the early 70's!
It was still perfeclty good and I gave it to a buddy to use with his weed burner.

Any tech worth being called a tech should know better than to overlook all weld seams as a source for a leak. Very small, nearly microscopic pinholes are difficult to locate and will sometimes be intermittent due to changing temperatures and therefore tank pressures. When all other possible points of a leak are exhausted we can't overlook the area around and under the mounting straps for our fixed tanks. This is a point of collection for entrapped moisture and often develops rust under the straps resulting in leaks. The brine solutions used to treat winter roads in many states has made rust a much bigger problem for tank life on RV's that see winter road use.

RE: your inherited tank, since it had an expiration date, actually requalification date, I will assume that it was a cylinder, not a tank. A significant difference. Tanks built in the 1940' are still in use frequently, where cylinders over 30-35 years old are fewer and fewer. Many of the older cylinders were lost to scrap during the transition to the OPD valve required by the government a few years back.